Combustion regulator



Oct. 5 19-26. 1,602,092

H. wlTz COMBINATION REGULATOR Filed April 1o, 1923 ...I LS..

IN IfEN TOR.

A TTORNEYS.

Patented Oct. 5, 1926.

UNITED STATESA PATENT oFElcE.

HENRY WITZ, OF OBERHAUSEN, GERMANY ASSIGNOR TO THE BABCOCK & WILCOX COMPANY, OF BAYONNE, NEW JERSEY, A. CORPORATION OF NEW JERSEY COMBUSTION REGULATOR.

Application led April 10, 1923, Serial No. 631,169, and in Great Britain December 28, 1922.

As is well known in the burning of any of the usual kinds of fuels, the best combustion' conditions are obtained when the percentage of CO2 (carbon dioxide) in the gases resulting from the combustion is maintained at or near some definite point, say, from 13 to 15 per cent. If the CO2 content exceeds the optimum found to give the best commercial conditions,` CO (carbon monoxide) is contained in the gases of combustion, while if the content is less than this optimum, there is present an unnecessary surplus of air.

One of the objects of the present inven tion is to provide an arrangement by which the correct combustion conditions may be automatically maintained inv the furnace, such regulations being controlled by the percentage of GO, in the combustion gases. Such combustion conditions may be controlled either by rel ating the supply of combustion air or t e supply of fuel, and the invention may be applied to furnaces burning any of the, usual forms of fuel.

One embodiment of the invention is illustrated more or less diagrammatically in the annexed drawing in which the invention is shown applied to a chain-grate stoker with coal as the fuel.

In the drawing, 1 is a `chain-grate Stoker of the usual type and carrying a fuel bed beneath a furnace chamber 1. An air sealing and ash and clinker collecting device 2 is provided at the rear of the fuel bed, the

front part of the grate, in the illustrative embodiment, being cut off from the rear portion by the boxes 3 and 4. Forced draft is supplied to the rear part of the chain gate,

l'i a the plates forming a series of ducts each having a damper 6 to regulate the iiow of air through the duct. Each of the dampers provided with an arm 7 connected to a rod 8, the length of the arms 7 preferably varying from front to rear, so thatfor a.

given movement of the rod 8, the dampers at the rear of the- 'rate will be open farther than the correspon ing dampers at the 'front of the grate. E

As a means for moving the damper 6, a water-power operated motor has been illustrated This motor has a cylinder 11 in which is a piston 10 connected through the the rod 8. A weight 12 is arranged to draw the rod 8 normally to the left of the ligure. To the rear of thecylinder 11 is connected a pipe 13 which, in turn, may be connected to a pressure supply pipe 16 or to an out-let pipe 17 by means of a three-way valve 14. When the valve 14 is set in position to connect pipe 16 with pipe 13, the water pressure will move piston 10 to the right of the figure to open the dampers 6, and correspondingly when the valve 14 is moved to close the connection between pipes 16 and 13 and to open the connection between pipes 13 and 17, the pressure in the cylinder 11 is decreased and the weight 12 will draw the rod 8 to the left of the figure to close the dampers 6.

In the illustrative embodiment, the threeway valve 14 is operated electrically by means of an armature 15 connected to the piston rod 9 with v.valve 14 and turned clockwise by the spring from asource of light 36 passing through an opening 34 in a screen 33. The amount of light willbe determined' by the position of the pointer 35 of any of the well-known measuring apparatus, such as the Ranarex Siemens or Uhling fuel gas testers, adapted to register continuously the COz content of the fuel gases.

With the apparatus so far described, if the CO2 content of the fuel gases exceeds the predetermined amount, the pointer 35 will then move upward or in the direction of the plus arrow of the ligure. This exposes more of the opening 34, so that a larger portion of the selenium cell is exposed to the light and its resistance is correspondingly decreased. strength in the winding 18 and correspond-- ingly the strength of the magnet 19 are thus increased, whereby thearmature 15 is at 20, this battery and env The current` tracted against the tension of its spring 15.

This turns the lthree-way cock 14 so that water under pressure is admitted. from the pipe '16 to the pipe 13 to move the rod 8 to the right of the figure, and thus open the damper 6 to supply more air into the fuel, this motion continuing until the percentage of CO2 is brought again within the desired limit.

Correspondingly if the percentage of CO2 decreases below the desired limit, the indicator 35 willbe moved downward or in the' and the pipe 13 to relieve the pressure back 20 of the piston 10. The rod 8 will now be moved to the left of the figure by the weight 12 to close the dempers to decrease the supply[` of combustion air.

he means for actuating the indicator or shutter may consist of a CO2 recorderof the Uhllng type, the indicating tube 37 of which is connected to a Bourdon tube 38 or other means sensitive to minute changes in pressure. `nected by means of a cord 39 with the shutter 35. Gases from the furnace enter the recorder through tube 4 0 and pass through the CO2 absorbing column 41, the inlet and outlet to which are e uipped with the usual standard orifices, as s own. The outlet terminates with the aspirator 42. Fluctuations in the CO2 content then produce variations in the suction maintained by the aspirator 42, and these changes of pressure alter the position of the free end of the Bourdon tube 1n a manner well understood.

In many cases it will not be possible toi vary the combustion conditions automatically between the extremes which may be found, and to warn the operator when the limits of adjustability have been reached, a system of slgnals have been provided. In the form illustrated, a bell 28 is connected with one pole of a battery 27, the other pole being connected through a wire 32 havlng a flexible portion 32 with a rod 31 attached to the. piston rod 9. The other terminal of the bell 28 is connected to each of a pair of contacts 30 arranged respectively on opposite sides of the rod 31. When the piston 10, and with it the rod 9, is moved to either end of its possible travel, contact is made between the rod 31 and one of the contacts 30 to close the circuit through the battery 27 and the bell 28 to notify the operator that the furnace conditions are out of the control of the automatic apparatus, heretofore described. As a further means of notifying the operator of the operating conditions, solenoids 21 and Thefree end of the latter is then con-A 22 may be placed in the circuit centaining the selenium cell S, the solenoid 21 having an armature I 21 held normally against a contact piece 26 by a spring 25 and solenoid 22 havin an armature 22 normally held away rom the con` tact member 24 by a spring 23: Each or these armatures 21 and 22 is connected to One lpole of the battery 27 and each of the contacts 24 and 26 is connected to the terminal of the bell 28, which is not connected to the battery 27. Vhen the resistance of the selenium cell S causes the current through the solenoids to increase, the solenoid 22 overcomes the resistance of the spring 23 and closes the circuit through the contact 24 to ring the bell 28. Similarly, when the resistance of the selenium cell S causes the current through the solinoids to decrease, the spring 25 will close the contact between 26 and 21 to ring the bell. The signalling devices last described may be used alone or 1n combination with the signal control by the rod 31.

While the invention ,has been shown in connection with a chain-grate Stoker, it will be understood that this is merely an illustrative embodiment, and that the invention may be used in connection with other forms of fuel. Moreover, while preferably the suply of combustion air is the element of combustion which is to be regulated, it will be understood, particularly where liquid or 'gaseous fuels are used, that the roper combustion conditions may be broug t about by regulating the supply of the fuel while the supply of air remains substantially constant, or if desired, both the fuel and the air supply may be varied.

I claim: l

1. In a furnace, means for supplying fuel to the furnace, means to supply combustion air to the fuel, and automatic means, con- .trolled by the CO2 content of the combustion gases, to increase the supply of combustion air when the C()2 content of the combustion gases exceeds a predetermined percentage, and to decrease the supply of combustion air when the CO2 content of the combustion gases is less than a predetermined percentage, an alarm device, and means for actuating said device when the CO2 content reachesl a given limiting value.

2. In a furnace, a fuel supporting grate, means to supply combustion air to the entire area of the grate, and means controlled by the C()2 content of the combustion gases, to vary the supply of combustion air to one part of the grate relatively to the amount of combustion air supplied to the remainder of loto, a. plurality of 20 supply combustion air to t air to the fuel during its travel through the chamber, and means, controlled by the CO2 content of the combustion gases, to vary the.

supply of combustion air to the fuel at the 5 rear part of the grate relatively to the amount of combustion air supplied to the front part ofthe grate.

4. In a furnace, a fuel supporting grate, means for supplying combustion air thereducts spaced longitudinallylbeneath a portion of the grate, dampers in said ducts, means controlled by the COz content of the combustion gases to vary the positions of said vdampers, said position 1 5 varying means including means permitting the grate relatively to the amo-unt of combustion air suppliedv to' the 25 remainder of the grate.

6. In a furnace, a chain grate, means to vsupply combustion airy to the entire fuel bed on the grate, and means, controlled by the CO,- content of the combustion gases, to 30 vary the supply of combustion air to the fuel at the rear part of the grate relatively to the amount of combustion air supplied to` the remainder of the grate, and to increase or decrease the supply more to -the rear' end 35 of said rear part than to the front end of said rear part for a given variation of the CO,v content.

, 7. In a furnace, a chain grate, meansfor supplying combustion air thereto, a plural- 40 ducts placed longitudinally beneath the rear portion of the upper run of said chain grate, and means controlled by the CO2 content of the combustion gases for varying the amount of said ducts.

ity of HENRY WITZ.

ofA air admitted to each 45 

